1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationSemiconductor devices Mechanical and climatic test methodsPart 40: Board level drop test method using a strain gaugeBS EN 60749-40:2011National forewordThis British Standard is t
2、he UK implementation of EN 60749-40:2011. It is identical to IEC 60749-40:2011.The UK participation in its preparation was entrusted to Technical Committee EPL/47, Semiconductors.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does n
3、ot purport to include all the necessary provisions of a contract. Users are responsible for its correct application. BSI 2011ISBN 978 0 580 64629 4 ICS 31.080.01 Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority o
4、f the Standards Policy and Strategy Committee on 30 September 2011.Amendments issued since publicationAmd. No. Date Text affectedBRITISH STANDARDBS EN 60749-40:2011EUROPEAN STANDARD EN 60749-40 NORME EUROPENNE EUROPISCHE NORM September 2011 CENELEC European Committee for Electrotechnical Standardiza
5、tion Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Management Centre: Avenue Marnix 17, B - 1000 Brussels 2011 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 60749-40:2011 E ICS
6、31.080.01 English version Semiconductor devices - Mechanical and climatic test methods - Part 40: Board level drop test method using a strain gauge (IEC 60749-40:2011) Dispositifs semiconducteurs - Mthodes dessais mcaniques et climatiques - Partie 40: Mthode dessai de chute au niveau de la carte ave
7、c utilisation dune jauge de contrainte (CEI 60749-40:2011) Halbleiterbauelemente - Mechanische und klimatische Prfverfahren - Teil 40: Prfverfahren zum Fall einer Leiterplatte unter Verwendung von Dehnungsmessstreifen (IEC 60749-40:2011) This European Standard was approved by CENELEC on 2011-08-17.
8、CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained
9、on application to the Central Secretariat or to any CENELEC member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central S
10、ecretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembour
11、g, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 60749-40:2011EN 60749-40:2011 Foreword The text of document 47/2094/FDIS, future edition 1 of IEC 60749-40, prepared by IEC TC 47, Semiconductor devices, was sub
12、mitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 60749-40 on 2011-08-17. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and CENELEC shall not be held responsible for identifying any or all such patent
13、 rights. The following dates were fixed: latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2012-05-17 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2014-08-17 A
14、nnex ZA has been added by CENELEC. _ Endorsement notice The text of the International Standard IEC 60749-40:2011 was approved by CENELEC as a European Standard without any modification. _ BS EN 60749-40:2011EN 60749-40:2011 Annex ZA (normative) Normative references to international publications with
15、 their corresponding European publications The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. NOTE W
16、hen an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies. Publication Year Title EN/HD Year IEC 60749-37 - Semiconductor devices - Mechanical and climatic test methods - Part 37: Board level drop test method using an accelerometer EN
17、60749-37 - BS EN 60749-40:201160749-40 IEC:2011 CONTENTS 1 Scope . . 6 2 Normative references . 6 3 Terms and definitions . 6 4 Test equipment . . 7 5 Test procedure . . 7 5.1 Test specimen . 7 5.2 Test substrate . 7 5.3 Solder paste . 7 5.4 Mounting method . 8 5.5 Pre-conditionings 8 5.6 Initial me
18、asurements . . 8 5.7 Intermediate measurement . . 8 5.8 Final measurement 8 6 Test method . 8 6.1 Purpose of test method 8 6.2 Example of drop test equipment . 8 6.3 Example of substrate-securing jig . 9 6.4 Example of distance between supporting points . . 9 6.5 Example of impacting surface 9 6.6 S
19、train gauge . 9 6.7 Strain gauge attachment . 9 6.8 Strain measurement instrument . .1 0 6.9 Test condition . . 11 6.9.1 Drop test conditions . 11 6.9.2 Test procedure . 11 6.9.3 Drop height. 12 6.9.4 Pre-test characterization . 12 6.9.5 Direction 14 6.9.6 Number of drops . . 14 7 Summary . . 14 Ann
20、ex A (normative) Drop impact test method using test rod . . 16 Annex B (informative) An example of strain gauge attachment procedure . 19 Figure 1 Example of drop test equipment and substrate securing jig 9 Figure 2 Position of strain gauge attachment . 10 Figure 3 Strain measurement instrument . 11
21、 Figure 4 Waveform of strain and electrical conductivity of daisy chain . . 11 Figure 5a Number of times of drop to failure 13 Figure 5b Pulse duration 13 Figure 5 Correlation strain and number of failures and strain and pulse duration . 13 Figure 6 Correlation between pulse duration and distance be
22、tween supporting points . 13 Figure 7 Correlation between the number of times of failure and the maximum strain. . 14 Figure 8 Direction of dropping . 14 BS EN 60749-40:201160749-40 IEC:2011 Figure A.1 Outline of test apparatus . 16 Figure A.2 Waveform of strain and electrical conductivity of a dais
23、y chain . . 18 Figure B.1 Equipment and materials 19 Figure B.2 Example of Attaching Strain Gauge and Guide Mark Dimensions 20 Figure B.3 Strain gauge attachment procedure, part 1 . 21 Figure B.4 Strain gauge attachment procedure, part 2 . 22 BS EN 60749-40:2011 6 60749-40 IEC:2011 SEMICONDUCTOR DEV
24、ICES MECHANICAL AND CLIMATIC TEST METHODS Part 40: Board level drop test method using a strain gauge 1 Scope This part of IEC 60749 is intended to evaluate and compare drop performance of a surface mount semiconductor device for handheld electronic product applications in an accelerated test environ
25、ment, where excessive flexure of a circuit board causes product failure. The purpose is to standardize test methodology to provide a reproducible assessment of the drop test performance of a surface mounted semiconductor devices while duplicating the failure modes normally observed during product le
26、vel test. This international standard uses a strain gauge to measure the strain and strain rate of a board in the vicinity of a component. Test method IEC 60749-37 uses an accelerometer to measure the mechanical shock duration and magnitude applied which is proportional to the stress on a given comp
27、onent mounted on a standard board. The detailed specification shall state which test method is to be used. NOTE 1 Although this test can evaluate a structure where the mounting method and its conditions, the design of a printed wired board, solder material, the mounting capability of a semiconductor
28、 device, etc. are combined, it does not solely evaluate the mounting capability of a semiconductor device. NOTE 2 The result of this test is strongly influenced by the differences between soldering conditions, the design of the land pattern of a printed wired board, solder material, etc. Therefore,
29、in carrying out this test, it is necessary to recognize that this test cannot intrinsically guarantee the reliability of the solder joint of the semiconductor devices. NOTE 3 When the mechanical stress which is generated by this test does not occur in the actual application of the device, implementa
30、tion of this test is unnecessary. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) a
31、pplies. IEC 60749-37, Semiconductor devices Mechanical and climatic test methods Part 37: Board level drop test method using an accelerometer 3 Terms and definitions For purposes of this document, the following terms and definitions apply. 3.1 device single electronic component to be surface mounted
32、 3.2 drop impact strength strength of the test substrate held by a jig that is dropped from a defined height, as represented by the number of cyclic drops that finally cause fracture on the joint between a device and a PWB copper land BS EN 60749-40:201160749-40 IEC:2011 7 3.3 strain strain of surfa
33、ce of substrate degree of stretching observed when the test substrate is distorted NOTE The strain is a numeric dimensionless quantity. 3.4 maximum strain tensile side (+) of the strain waveform 3.5 pulse duration duration between the instant when the acceleration first reaches 10 % of its specified
34、 peak level and the instant when the acceleration first returns to 10 % of the specified peak level after having reached that peak level 3.6 momentary interruption detector equipment which detects extremely short electrical discontinuity (momentary interruptions) in a daisy-chain circuit 4 Test equi
35、pment The equipment shall be selected to satisfy the test conditions specified in Clause 6. Alternatively, the test method described in Annex A can be used. 5 Test procedure 5.1 Test specimen Unless otherwise specified, specimen devices shall be of a structure that allows continuity to be checked (e
36、.g., daisy chain). They shall be of a design based on the same specifications as devices in actual use. The test specimens shall be on a daisy-chained substrate on the lead frame of a surface mounted device or on a substrate that is a carrier of a BGA, LGA, or SON, or the actual device shall be used
37、. NOTE When using daisy-chain connections, care should be taken not to cause any failure in wiring patterns on the test substrate. For example, the wiring patterns should be drawn in a crosswise direction on the test substrate, not in a longitudinal direction. 5.2 Test substrate The test substrate s
38、hall be prepared in accordance with the relevant specification, preferably using a substrate of the same structures an actual electrical device. Unless otherwise specified, a solder mask defined (SMD) land is desirable for a BGA and a non solder mask defined (NSMD) land for a QFP. For a BGA, it is d
39、esirable to match the land size of the test substrate with the land size of the package. 5.3 Solder paste The solder paste shall be prepared in accordance with the relevant specification. BS EN 60749-40:2011 8 60749-40 IEC:2011 5.4 Mounting method The mounting method shall prepared in accordance wit
40、h the relevant specification. However, one test specimen shall be mounted in the centre of the test substrate. 5.5 Pre-conditionings When specified in the relevant specification, carry out moisture soaking and soldering heat stress testing before the board level drop test. 5.6 Initial measurements T
41、he initial measurement shall be carried out in accordance with the relevant specification. 5.7 Intermediate measurement Intermediate measurement shall be carried out in accordance with the relevant specification. NOTE When determining failure after a drop test, a failure can wrongly be considered as
42、 acceptable because of electrical contact of a disconnect. Therefore, when determining failure, checking the daisy-chain signal lines with a momentary interruption detector or other similar equipment is advised. When using this technique, the resolution of the momentary interruption detector shall b
43、e capable of detecting 100s of momentary discontinuity. 5.8 Final measurement The final measurement shall be carried in accordance with the relevant specification. A sufficient number of failures from the test lot shall be subjected to failure analysis to determine the root cause and to identify the
44、 failure mechanism. Each failure site shall be clearly identified as “device failure”, “interconnect failure”, or “board failure”. 6 Test method 6.1 Purpose of test method This test method specifies the drop test conducted with the fall height based on measured strain using a strain gauge set on the
45、 test substrate. NOTE This test method uses drop test equipment, a substrate-securing jig and a strain measurement instrument. Because the test equipment is verified using the value of strain measured by a strain gauge attached to the surface of the test substrate, the test result does not depend on
46、 the drop test equipment or the substrate-securing jig. Accordingly, this standard does not prescribe the drop test equipment, the structure of the jig, or its form Correlation of a test result with the device and equipment type is straightforward since the test results are quantified in terms of th
47、e strain values. However, details of the device and equipment should be recorded. 6.2 Example of drop test equipment The drop test equipment is designed to drop a substrate-securing jig with a protrusion on its base, from a specified height onto a collision plane to apply the impact that would resul
48、t from a free fall or similar situation (Figure 1). BS EN 60749-40:201160749-40 IEC:2011 9 Arm Example of test equipment Strike surface Base plate Hanging wire Example of substrate securing jig Strike surface Screw Test substrate Component Base plate Substrate -securing jig Collision part IEC 1619/1
49、1 Figure 1 Example of drop test equipment and substrate securing jig 6.3 Example of substrate-securing jig Unless otherwise specified, the substrate-securing jig shall be constructed to allow the attachment of the test substrate with screws, and give a drop impact to the solder joints. The test substrate is fixed so that the device is in the centre of the substrate-securing jig. Unless otherwise specified, the colliding interface shall be a hemispherical protrusion
